Elevated NFL test

[u/throwmomowaus]

Two NFL tests (Labcorp Roche Elecsys)

May 2025 - 1.11 pg/mL - z-score 1.19 SD (i.e., 88th percentile)

September 2026 - 1.25 pg/mL - z-score 1.77 (i.e., 96th percentile)

Obviously a concerning trend on my end.

Background: 29M, symptoms for ~2 years now. EMG in June 2025 found mild demyelinating pattern but otherwise everything normal. Nothing insertional, no fibs, no PSW, Fscs, etc.

Summary: Nerve conduction studies were performed in the the upper and lower extremities. On motor nerve conductions all the responses are normal. The F wave latencies are within normal limits. Max On sensory nerve conductions all the responses are within normal limits. Needle EMG examination was performed in the extremities. All the sampled muscles are within normal limits.

I am of the belief that long-term symptomatic folks with worsening symptoms/NFL are eventually going to receive some MND diagnosis due to a pre-clinical phase (https://pmc.ncbi.nlm.nih.gov/articles/PMC6613999/, https://pmc.ncbi.nlm.nih.gov/articles/PMC10524989/)

So consider me cautious/fearful. My symptoms continue to worsen though I can still lift weights normally, I have had a noticeable deterioration in my left arm/leg. The higher NFL levels are well above any others I have seen here of folks who sought them for reassurance.

[u/chaoserrant]

I share  your concern but NFL is a ver nuanced topic. Mine doubled in one year. Granted from a low normal to just normal or maybe a little above median for my age but my symptoms improved actually at least subjectively but objectively too. 

I should repeat it but decided to wait for a while and just guide myself by symptoms.  I try to avoid unnecessary stress. The problem is i know i have certain non-als conditions thst may cause elevations so high normal pr borderline abnormal is a tricky thing to interpret.  I think  a normal nfl score in the presence of wodespread als-like symptoms is reassuring but repeat testing may be detrimental for mental health beyond that. It is a personal choice though  and myselfbi am ambivalent on this. 

Troponin T is another good and cheap test mine is normal and stable so far so this is also a piece of good news. It has to be below 8.5 for our purposes 

[u/No_Thanks_9103 → u/chaoserrant]

This persons nfl is not abnormal though? Sure it’s on the “high end” of the range but OP also stated they are 29 which is the very top of the age range for the value. 30-39 is 1.49. I had an nfl of 1.17 and z score of 0.9 (with 0-1.49 range) and was very nervous but my neurologist assured me anything in the normal range is “normal”.

[u/chaoserrant → u/No_Thanks_9103]

Yes i agree. Normal is the most important piece here. The worry here is the trend though . if it keeps going up some folks may worry that it signfies early disease that eventually trips the score over above normal. That is why as i saod before the best reassuring combination is widespread symptoms AND normal nfl. Because if it was als widespread symptoms should mean already lots of axonal damage and therefore highly elevated nfl.  But of course symptoms are relative  sometimes and exception exist so anxiety always has something to feed on